A strategy for Nethack progress?

To answer your question, yes. If you're having trouble in any RPG the solution is almost always to level up more or acquire superior gear. However if you don't know what your options are at certain points in the game it can be very relentless due to the pseudo-artificial difficulty of, simply put, not knowing. Which leads me to my next and most major tip...

Use the NetHack wiki! ( http://nethackwiki.com/wiki/Main_Page )

It has so many great tips and tricks for both new and old players and I learn something new every time I visit it. Now it DOES have some gameplay spoilers but the majority of it is stuff you'd never find out on your own so you shouldn't feel bad about using it. Nothing I've seen on the NetHack wiki has ruined the game for me. I haven't ascended yet either but I recommend one of the following classes for your first time: Knight, Valkyrie, Barbarian, Samurai, Wizard.

In my opinion Knight is the easiest class to ascend with. Great starting gear, a horse for jousting, you can dip very early for Excalibur. Valkyrie is great too, and very similar to Knight with her early acquirement of Excalibur. Barbarian not so much, he's mostly just for learning the ropes of the game and then you'll probably want to use another class. Don't get me wrong though, many players started with the Barbarian and have never played another class! Samurai can be very versatile like the Knight even very early on in the game and his starting weaponry is very versatile as well.

As I said, I have never ascended for obvious reasons but I do have a good amount of knowledge concerning this game and other roguelikes. If you have any questions feel free to ask and I will be glad to help you on your road to ascension.

I've finished my game for the wizard so I can outline the strategy which was working for me. I don't know what parts you know exactly, so I will tell you everything I consider important.

First of all, dump your quarterstaff and try to use daggers as your main weapons. They can be not only wielded, but also thrown, and if you become skilled in using daggers, you will be able to throw several daggers at once. Ten daggers or so is a good number to start with. Also I'd find an armor which doesn't hinder spellcasting (like studded leather armor) and try to enchant the cloak. Obviously enough, you should try to learn as many spells as possible and get all the resistances you can.

I advise not to go into the Gnomish Mines when you find the entrance. You can reach the Minetown easily, but you won't be able to reach Mines End yet and get out safely. So instead of going to the Mines, go to the Oracle and then to Sokoban. Sokoban should train your strength because you will move boulders a lot, which is helpful, and also you will get some gold and a gift at the end, which is, as you probably know, either bag of holding or the amulet of reflection.

After Sokoban you should go to Minetown and try to reach Mines End. Minetown has an altar and if you're lucky, it will be your god's altar. If that's the case, you should offer corpses of recently killed monsters to your god until you get Magicbane. This is a magical dagger, which is extremely helpful in combat.

Mines End will give you a luckstone (and also some gems). You have to fight a lot of monsters there though, so stand on the stairs and use Elbereth to keep them off. If you have Magicbane, engraving done with it will be harder to erase.

If you have survived Mines End, you can return from the Mines to the main branch and safely descend until you come to the level with the quest portal. Don't worry, if you haven't reached level 14, the first quest level usually has Wraiths whose corpses raise your level when eaten. If you still need to gain levels, descend lower in the main dungeon. Usually I don't linger in the level after I have explored all the passages. You should aquire necessary level before you reach Medusa's island.

When your level is enough, you can finish your quest. Your nemesis won't be tough if you know how to hinder his healing. After you finish him, you get your quest artifact which replenishes your power, and later on you shouldn't have any problems.

That's the basics of the wizard strategy.

With regard to your one specific comment, many of the classes have quest levels significantly harder than the normal dungeon. Unless I feel I'm quite confident (GDSM, artifact weapon, 3-star cloak, emergency wand, etc) I'll continue down the dungeon to the castle and possibly pick up the /WoW before returning to the quest level.

I'll try to edit in more later.

This is not strictly an awnser to any of your questions but I find a good strategy is to leave a delibrate Bones File full of good gear and then come back for it. I highly recommend trying out this method as it worked for me with all roles.